Cotton picking machine



April 12, 1949.

COTTON PICKING MACHINE Filed Dec. 11, V1944 4 Sheets-Sheet 1 M. D. RUST l 2,466,969 A l April 12, 1949. M. DL RUST COTTON PICKING MACHINE 4 Sheets-Sheet 2 Filed Deo. 11, 1944 @www April 12, 1949, M. D. RUST COTTON PICKING MACHINE 4 sheets-sheet s Filed Dec. l1, 19 44 A 3mm,

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coTToN Prcxrne MAGHINE Filed Dec. 1,1, 1944 4 sheets-sheet 4 Mack 11 Rast, f

AEN"

Patented Apr. 12, 1949 .UNITED .sIArzEfs PATE-Nr 'or-FICE 'COTTONHCKING MACHINE AMack;D.Rusi Phoenix, Ariz.

Application December 11, 1944, Serial No. 567,651

14 Claims.

My invention relates to v'cotton picking machines of the `Rust type, Isee "Patents fN'os. 2,058,514 issued October 27, P1936, 2,076,598 -issuede-April 13, l1937,-ancl'2,085,046 issued JuneZl, I1937, forexamples.

In a machine of the Rust 'type "there is pro- -vided la main frame of elongated construction having'azn'liddlespace (ir-chamber; at the-ends of this frame'sprocket shafts aremount'ed about Whichshafts and-'the frame run upper andlower conveyor chains carrying r-slats 4on which are mounted picking spindles. The spindles have rollers which run on tracks mounted'on the outfsideof the workingsideof the frame; the Working side-of the frameis outwardly curved-while the opposite side is straightinthe usual construction. The backingmembers for the tracks are mounted on the v'frameloetvveen it andthe slatted conveyor.

Heretoiore, when itihasbecome necessary to replace aV track or'tracks,fit wasnecessary to partially dis-assemble'the conveyor lin order to get at the tracks. This was a'tediou-s' and time consuming operation often A keeping the* machine out of commission 'forseveral hours. `It is therefore the principal object=of thepresentinvention to provide means lforeliminating this* objectionable feature and to providefmeans whereby theitracks and therbacking members'can bequicklyand conveniently removed and replacedwithout `disturbing the conveyor andwit'h'out having toput the machine outof commission lforany considerablv length of time.

Acaingit is an object toprovide separate track backing members for groups of two or'more'hori- 4zontal rows-of spindles-fandfto makeeach track backing member removable and replaceable 'via the chamberfof the framewithout-disturbing the spindle conveyor or any of rtheotl'ler track backing members, thereby making ity possible rtoiremove and replace the-damaged track in a min-imum `ofttime and :with the kleast inconvenience.

Other objects will in fpartfbe obvious v'and 'in part be'pointed out hereinafter.

To the attainment of fthefa'foresaid objects and ends the invention still vfurther :resides in the novel :detail-s lof .-construction, 'combination :and arrangement Iof parts, :all of "which will 'be l'irst fully described.: in 'thesfollowing detailedl description,l and i then;` bef-particularly pointed out in the appended zclaims, reference being had `to the acccmp anying drawings, in vwhich:

Fig. il a part -'horizontal section ftaken Vap- ,proximatelyaon the line l 'of?2Eig..-2',: and apart plan lview :of :the mainframe-:of .1a Rust cotton 5I 3 and 4 are connected by'a-crossbar l'PR r2 picker and the adjacent picker-spindlesand'slats on the working" side- 'of 'f the'frame.

Fig. 3 is an enlarged horizontal section and part plan View'ofaportion of theistructure shown in Fig. l,Y taken onthe line -3"3` of lFig. 4.

Fig. 4 is an enlarged verticalcrosssectionlv on the line 4-4 Aof Fig.'3,'the parts 410534,f43in5the lower half'of the gure'being shownin the'posi-'tionthese parts occupywhenmovedfto the'po sition indicated bythe dottedlines in "Fi-gf 1.

Fig. 5 is an velevation ofthe'tubular'post and the adjacent ends of two track backinglmembers, parts lbeing broken away.

Fig. 6k is asecti'on 4onfthe linefli--G` `of Figure "5.

Fig. '7 is a detailperspective viewhereinafter again 'referred to.

Fig. 8 isa detail horizontal sectional view on approximatelythe 'line'4-4' of LFig. 3 hereinafter again referredv to.

Fig. 9 is adetail view similarlin part tov Fig. l1,

showing `a modified construction.

Fig. 'l0 is -a *section on the line l0-l0 of Fig. 9.

Fig. -11 -is a `section 'onthe line H--ill of Fig. 10.

Fig. 12-isfan enlarged'detail section of the rear portion of the spindleba'cking, taken inthe plane of the linelIZ-I2 of 13.

Fig. 13 is a fragmentary detail elevation of la portion of the structuresh'ownin A Fig. 12looking in thev direction offthe'arrow in"Fig. I2.

Fig. 14 is a detail vievv=showing how thel post Z ln is vertically adjustably lmounted.

In the drawings in'whichlike numbersfof reerenceindicate like partsinall the figures, the main frame is shown constructed of -two end. channel posts l and 2 connected along one side by upper and lower angl'eirons' and 3, respectively. On the front or working side v'off the'frame are upper and lower-curvedfangle bars and '4, respectively. The bar-s6 and 4 cooperate with other fixed anglebars I0 and Il', respectively, 'to carry the roller-chain 'tracks '94, for the slatted conveyor (I2, I3, 15').

Thebars '.'andl are connected byfa crossbar vl labout vmidway the -ends of the-frame, the bars Filler plates 3 are welded to thebars 354 andi, 46 respectively at vvtheir ends. The channel posts I and 2 are welded tothe bars3, '4, 5, 6, and to the plates-ll, 9X and together '#with the back pl-ateB constitute the principal elements of the main frame-of the machine.

yshown in Fig. 1.

The spindle carrier comprises upper and lower endless chains composed of links I2 and rollers I3 which run on tracks I4 secured to the angle bars 4 and 6 of the frame and other angle bars I and II suitably xedly supported (not shown) from the frame in a well known manner (see patents aforementioned). Slats I5 are mounted on the chains in the usual manner and carry the picking spindles I6 whose rollers I'1 engage tracks I8 mounted on the outer side of the frame. In the preferred embodiment of the invention there is provided one track for each two horizontal rows of spindles although if desired a separate track for each row may be provided.

Each track I8 has a neck I9 and a head 28 similar to the neck and head shown in Fig. 5 of Patent No. 2,058,514 aforesaid.

The post 2| is provided with va keyhole slot 22 to receive the neck and head of the track I8,

see Figs. 3 and 4. The post 2| is welded to the and serves in `part to stiften the frame and in part as a means by which the track backings are mounted on the frame as will be more clearly understood later.

The track backing members each comprises a longitudinal bar against which the track I8 lies and is pressed by the spindle rollers during the operation of the machine. Preferably this track backing member is made in two sections, a back section 23 and a front section 32. The back section 23 extends rearwardly from the post 28 with4 which it is endwise slidably connected in any suitable manner, preferably by means of a dovetail block 24 welded or otherwise suitably secured to the back face of the bar, the dovetail 24 fitting between dovetailed blocks similarly secured on the front face of the post 28, see Figs. 5 and 6. The bar 23 has a lug 26 which when the `bar is in place engages a lug 2'I fixed to the post 28 to limit the rearward movement of the bar as it is inserted in place. In lieu of the lugs 26, 2'I or in addition to them I may provide stop shoulders on the rear dovetail blocks 29 vthat are carried by the bar 23 and t dovetail slots in a vertical support 3I that is secured to the channel post 2, see Figs. 1 and 7.

The dovetail blocks 29 have reduced dovetails 30 to iit the slots of the post 3l.

The rear track backing member 23 is also preferably provided at about its mid-length with another dovetail block 24 to t dovetail guides, similar to the guides 25, on the angle post that is welded to the bars 4 and 6. It should be understood that the intermediate and rear dovetails are preferably made progressively smaller than the front one so as to slide freely through the front one in removing and replacing the member 23 as will more clearly appear presently.

The front section of the track backing member, at its rear end has a dovetail block 58 correspondingto block 24 and tting the dovetail guides 25 of the post 28, see Figs. 1 and 5. At its forward end the bar 32 is slit as at 33 to provide a tongue 34 which is bent inwardly as best This provides a support for the neck of the track I8. The front plate 36 which is welded or otherwise secured to the front end of the bar 32 is slotted, as at 42, to permit the neck I9 to pass so that the head 20 may lie in front of the post 2| while the neck lies in the narrow part of the keyhole slot 22,

track backing member receives the greater strain I provide a truss in the form of a channel beam 35 which is welded to the back of the bar section 32 and extends from end to end of the same.

The plate 36 has stop notches 3l to engage the stop lugs 38 on the post 2| to limit the outward movement of the bar 32 to a position to line up with the rear section 23 when in place.

Pivoted between ears 39 on the back of the truss 35 is a toggle latch 4l! held in either of two positions by a spring 4I. The hinged end of the latch rests in a saddle 48 and has an elongated pin hole 41 for the hinge pin 43 so that the thrust is not applied to the pin but against the saddle. When the latch is in the normal or latching position (Figs. 1 and 3) its free end 45 lies in the larger part of the keyhole slot 22 and presses against the inner flange of the post 2I thereby holding the bar 32 at its front end against getting loose due to vibrations of the machine when in use. The spring 4I constantly tends to tighten the bar in Aplace and to that end the curved free end of the latch is preferably made eccentric to the pivot 46.

The outer faces of the bar sections 23 and 32 are provided with wear strips of any suitable material as for example fibre. These strips 43 are secured to the bars in any suitable way and constitute, functionally, a continuation of the guide plate 44 that is fixed to the frame in the usual manner.

The track I8 may be made of any suitable material and per se is not of the present invention. The tracks may be made as disclosed in Patent No. 2,058,514 aforesaid if desired.

With the parts in the position shown in Figs. l and 3 and the upper part of Fig. 4, in order to remove the track backing member and its track, the operator reaches down into the chamber X of the frame and throws back the latch 4D to the position shown in dotted lines in Fig. 1 where it is held by toggle spring 4I. He then pulls in the front end of the member 32 using its rear end somewhat as a pivot and lifts that section out of the machine. He next moves the rear section 23 from right to left in Fig. l until it comes into the place where the front section was and then he swings it inwardly as he did the front section and lifts the back section up out of the machine. The track I8 is now exposed and the attendant reaches in, unhooks the head and pulls the track forward and out through the chamber X.

'I'o replace the track or place a new track the above operations are reversed. First the track is put into place, then the rear section of the member 23 is replaced and finally the iront section is put in and snapped into locked position by throwing the latch forward again.

In Figs. 9 to 14 inclusive I have shown a modication of my invention. In these figures those parts which correspond to similar parts in the preceding figures bear the same reference numbers plus the index letter a.

In this embodiment of my invention the track backing member front section 32SL is made of simple flat bar steel rolled and formed to shape required. It is not provided with the channel shaped reinforcing truss 35 and has, as support in lieu thereof, two removable posts 54. These two vertical posts 54 are attached to the top and bottom frame members 4 and I0 Iby means of cap screws 56 and tapped mounting blocks or brackets place between lugsfil zand5-2sasshownz-and tapped lightly doWnward'with-.a vhammer vorfany. suitable tool, Aandito remove same thereverse applies. Tapping ,the wedge :fromz'be'low toloosenzand removingisame permitsithe. frontrendfof the track .backing members :front section to .be swung i inwardly for removal from -zits .workingtposition Prior-to removal :of-anyftrack `backing member section, howerergit isnecessary with thisconstruction to remove'zboth` of I the Avertical .posts f 54.

AThe fron-t support postlzlazis constructedasa tubular member rather than as a channel-shape memberjbut it isxprovidedfwithlithe `same general arrangement :of .key hole slotsi-a to `r receive "the neckandf head1 ofithetrackfl 8. This. post is'fbolted tothe topwandztbottomsrailsmndloan .beremoved A- or f adjusted vertically if necessary .'byl useof reap screws :56 :and :slotted f brackets :55X welded Sto `the topxandi bottom '.bars. .It L is:- notrelied fon tto perform as fa Istiilening :member for 1 the main frame, although yfof :course .this 'member when bolted :into position :does :naturally supplement the strength offthe main framesstructure.

rArrangement 'of the mid-.postA 28a. is showniin Figs. 9'and 12. :It include'saan "angle-.n placeiof the tubepreviously-shown. .instead'ofzthe vtapered dovetail connections 4.'l'ieretofore shown, fqthere 2 is used-a flatbar-51fFigs-r9, l2 andlB) Sweldedtto .track backing-1 member 43i a, :which 'jointly engage the lugs on notched ibarz .boltedito'post 28s. The extreme rear endaoffbackin'gmember $2a'wll be seen to: rest fagainst 1 a portion of: thein'otched bar-63 which is `falso'bolted to the :otherleg 4fof post langle 2li-e. Member i322' 'is -'thus vheld :at Ithe 1 rearv against :movement fin :all directions xexcept pivotingfand 1 forwardly, which'znotions permit proper;removal `when desired. Llhe bar has short legs 59 between which theirear'errdsrof the'mernbersa lie. The bar-i63falso has short legs fell :between iwhich lfthe Airont ends of :menioers' 2.13a lie.

Therear section 23a; oli` the; track backingfmem- :ber :is supported vertically land .against iinwartl motionat the frontby notchedlbarfS withthe bentlugsl'tkl asshowninFig. 1:2. 'The rear-fend of; memltier2%??3V is. supported Vertically'fand against inward mov-ementl'by-theinotched angle .post'll which is secured Ytomai'n frame Jpost member by cap screws `56. Member 23a lis Y'held vagainst outward and longitudinal motion by means s of v a cap lscrew F56V passing fthrough rang-le 'Jiliand threaded into 'memberf 23a. -Angleilll is securedi to post 45a by-*bofltsi andfi'sioapablefof-adjustment as necessary vertically or laterally-'byfmeansff suitably placed slotted bolt. holes.

I have 'found in rpractieelthat it isipossible-f'to remove. and replace the'tracks Without removing the rear section of 'thetrack backing member. fIn all cases soYiar-it has-'onlybeen necessary toire-- move the front'section offthe trackbackingrmember in order toremovef-the .f tracksathemselves.

'From the foregoing fdescription taken? in confnection with the accompanying drawings #it is thoughtf the complete construction: and operation as well as'the `advantagesof-tlieisarne willbeclear to thoseiskilledini thesart.

6 iwhile 'Iihaverdisclosed arpreferred Veirrbodirnent of` theinvention I wish it understoody that: numerous .changes in the idetails VAof construction :can readily be made by= thoseskilled in the art without departing romthefspiritofrthe invention within "the scope 1 of ithe V.appended f claims.

What '.If claim is:

'.1. In arcottonzpicking/machine whereinv is provided a main framearoundan'd `adjacent'vrhi''ch travels ani endless slatted spindle carrier oniwhich horizontalrows .of spindles `having rollers fare mounted, sai-diranno having achamber, there being a: track for-l'eachtwo horizontal rows of spindlession'whichrtrack-the rollers run: the improvement' which: includesa track-backing -bar for each track, saidl-bar :comprising a front sectionand abackfsectionheld end to-end, a supportfor'the front vend of the front section,a supportfor the rear 'end-ofthe back section, anda support l'for theacljacent ends ofthe bar sections, and means toinrountisaid. bar sections on said supports.

2. In a,cotton-pickingmachine Whereiniisfprovideda mainframe around and adjacentI which travels' an endless slatted spindle carrier on which horizontal rows yof spindles having rollers A' are mounted, risaid frame having :a chamber, vthere beingffa tratck for each two .horizontal rows fof spindles :on .-whichtrack therollers run: the irn- .provement which includes l a Itrack-backing bar for eachtrack, said bar comprising .a frontsectionanda ba'ckisection hel'dzend; to. end, a support forthe frontfend of the1front section, aV support.

for the rearfend fof the'back section, a support for the adjacent ends of the bar sections, and means tomountsaidibarsections on said supports, said.adj'acenteends-fsupport being located on the .chamber `side iof.;said bar yand said bar sections .being endwise'slidably heldon the support by their mounting means.

3. IIny a cottonpicking machine wherein is provided-amain frame aroundand adjacent which travels an endless 'slattedspindle carrier on which horizontal yrows of .spindles vhaving rollers are mounted, 'said .frame Vhaving a chamber, there being ca .track tfor .each two .horizontal rows "of spindleszonfwhich.track'therollers run: the improvement which :includes a track-backing vbar foreach rtrack, said barf comprising i a front sectonfzanda backsectiongmeansfor mounting said .bar isectionsrin endwisealignment on said frame, said mounting means includinga supporton the frame for the rear'end'of Ythe backsection, a support rforthe adjacent vends of the bar sections which 'support includes .bar .holding elements throughwhichlthe rear-bar section may be endwise displ-acediinto'thespace normally occupied bythefiront-sectionfof the'bar aiter'that section shall have'been'fremoved, and means-releasably supporting ithefront end of the front `section of the bar.

4. In'a cotton pickingl machine wherein is provided-a main'frame around'and adjacent which travels an endless slatted spindle carrier on which horizontal vrows vof spindles having rollers are mcuntcd,ffsaid'frarnehavingfa chamber, there being a track 'for each -two horizontal rows of spindles fon which'traclcthe-rollers run: the improvement Vwhich vincludes fa Atrach-backing bar for each'track, said bar comprising a front section .anda backsection,-means'ior mounting said bansectons'inxendwise alignment'on said frame, said fmounting -means including av support` onthe frame yfor the -rear yend of the "back section, Ja support ffor theladj acent lends Yof the' bar f sectionsl which support i'nclu'des "bar holdin-g elements through which the rear bar section may be end- Wise displaced into the space normally occupied by the front section of the bar after the front section shall have been removed, a support for the front end of the front bar section which support includes a stop limiting the outward movement of said front end and means ior holding the bar against said stop to prevent accidental inward movement of said front end.

5. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being a track for each two horizontal rows of spindles on which track the rollers run: the improvement which includes a track-backing bar for each track, said bar comprising a front section and a back section, means for mounting said bar sections in endwise alignment on said frame, said mounting means including a support on the Tranne for the rear end of the back section, a support for the adjacent ends of the bar sections which support includes bar holding elements through which the rear bar section may be endwise displaced through the space normally occupied by the front section of the bar after that section shall have been removed, and means releasably supporting the front end of the front section of the bar, the last named means comprising a spring-loaded latch device engaging said front end support and continuously forcing the front end of the front bar section against its stop.

6. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle cairier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being a track for each two rows of spindles on which track the rollers run: the improvement which includes a sectional bar for supporting said track, said bar including at least a front section and a back section held in longitudinal alignment, a support for the adjacent ends of the sections, an intermediate support for the back section, means to mount said back section on its support for endwise movement of the bar section, means limiting the rearward movement of said back section in its supports, and means to support the front section of the bar.

7. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being a track for each two horizontal rows of spindles on which track the rollers run: the improvement which includes a sectional bar for backing said track, said bar including at least a front section and a back section held in longitudinal alignment, a support for the adjacent ends of the sections, an intermediate support for the back section, means to mount said back section on its support for endwise movement of the bar section, means limiting the rearwa-rd movement of said back section in its supports, and means to support the front section of the bar, said last named means including elements on the support for the front end of said front section to hold said front end against up and down movement and limiting its movement toward said track and said carrier, and releasable means constantly urging said front end outwardly toward said track and said carrier.

8.v In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which rows of spindles having rollers are mounted, said frame having a chamber, there being a track for each two rows of spindles on which track the rollers run: the improvement which includes a sectional bar for supporting said track, said bar including at least a front section and a back section heldin longitudinal alignment, a support for the adjacent ends of the sections, an intermediate support for the back section, means to mount said back section on its supports for endwise movement of the back section, means limiting the rearward movement of said back section in its supports, and means to support the front section of the bar, said front section having a longitudinal slot with an inwardly bent tongue to receive the front end of said track, said support for the front section having a keyhole slot for the reception of the front extremity of the track and anchor same.

9. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which rows of spindles having rollers are mounted, said frame having a chamber, there being a track for each two rows of spindles on which track said rollers run: the improvement which includes a sectional bar for supporting said track, said bar including at least a front section and a back section held in alignment longitudinally, a support for the adjacent ends of the sections, an intermediate support for the back section, means to mount said back section on its support for endwise movement of the back section, means limiting the rearward movement of said back section in its support, and means to support the front section of the bar, said front section having a longitudinal slot with an inwardly bent tongue to receive the front end of the track, said support for the front section having a keyhole slot for the reception of the front part of the track and anchor same, the rear end of said front section of track being mounted so that the front end of said front section can be swung inwardly into said chamber on said rear end as a pivot.

10. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which rows of spindles are mounted and having rollers, said frame having a chamber, there being a track for each two horizontal rows of spindles on which track said rollers run: the improvement which includes a sectional bar for supporting said track, said bar including at least a front and a back section in longitudinal alignment, a support for the adjacent ends of said sections, means to mount said back section on its supports for endwise movement of that section, means limiting the rearward movement of said back section in its supports, and means to support the front section of the bar, said front section having a longitudinal slot with an inwardly bent tongue to receive the front end of said track, said support for the front section having a keyhole slot for the reception of the front end of said track and anchor same, the rear end of said front section being mounted so that the front end thereof can be swung inwardly into said chamber on said rear end of the section as a pivot.

1l. In a cotton picking machine in which is provided a frame around and adjacent which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, there being a track for each two rows of spindles on which track the rollers run: the improvement which includes a sectional backing bar for said track, said bar including at least a front section and a back section in longitudinal alignment, a support for the adjacent ends of said sections, a support for the front and the back ends, respectively, of said bar, means to mount the back section of the bar on its supports for endwise movement, means limiting the rearward movement of said back section in its supports, and a truss secured to the back face of said front section of said bar.

12. In a cotton picking machine wherein is provided a main frame around and adjacent Which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being at least one track for each two horizontal rows of spindles on which track the rollers run: the improvement which includes a track-backing member for each track, said member comprising a front Section and a back sec tion, means for mounting said member sections in endwise alignment on said frame, said mounting means including a support on the frame for the rear end of the back section, a support for the adjacent ends of the sections which support includes holding elements .through which the rear section may be endwise displaced into the space normally occupied by the front section after the front section shall have been removed, a support for the front end of the front section which support includes a stop limiting the outward movement of said front end and means for holding said front end against said stop to prevent accidental inward movement of said front end.

13. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being at least one track for each two horizontal rows of spindles on which track the rollers r-un; the improvement which includes a track-backing member for each track, said member comprising a front section and a back section, means for mounting said member sections in endwise alignment on said frame, said mounting means including a support on the frame for the rear end of the back section, a support for the adjacent ends of the sections which support includes holding elements through which the rear section may be endwise displaced into the space normally occupied by the front section after the front section shall have been removed, a support for the front end of the front section which support includes a stop limiting the outward movement of said front end and means for holding said front end against said stop to prevent accidental inward movement of said front end, said last named means comprising a lug on said front end, a lug on said support for the front end of said front section, and a wedge between said lugs.

14. In a cotton picking machine wherein is provided a main frame around and adjacent which travels an endless slatted spindle carrier on which horizontal rows of spindles having rollers are mounted, said frame having a chamber, there being at least one track for each two horizontal rows of spindles on which track the rollers run: the improvement which includes a sectional member for backing said track, said member including at least a front section and a back section held in longitudinal alignment, a support for the adjacent ends of the sections, an intermediate support for the back section, means to mount said back section on its support for endwise movement of the sections, means limiting the rearward movement of said back section in its supports, and means to support the front section, said last named means including elements on the support for the front end of said front section to hold said front end against up and down movement and limiting its movement toward said track and said carrier, and releasable REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date Rust et al. Oct. 27, 1936 Number 

